The invention relates to an open-end spinning machine including a spinning rotor and a pair of draw-off rollers, equipped with a thread tube adjacent the spinning chamber. The thread tube is constructed as an ejector nozzle which is capable of transporting the end of the thread back into the opening of the spinning chamber for reattachment to the fibers located therein.
In open-end spinning machines, a thread breakage is repaired by transporting the end of the thread into the fiber collection groove of the spinning rotor in the spinning chamber so that the end of the thread reattaches to the fibers located in the collection groove and the new thread is then pulled out of the spinning rotor. Whenever the spinning machine is stopped, thread breakage takes place, so that, when an open-end spinning machine is restarted, all the broken threads at a, sometimes, large number of individual spinning stations within the machine must be repaired prior to start-up. Until the present time, a requirement for automatic thread reattachment was that the end of the thread to be reattached had to be within the suction region of the spinning chamber and, more particularly, in the thread draw-off channel of the spinning chamber, at the time when spinning is resumed. It had been proposed to fulfill this condition by providing that the draw-off mechanism for the thread is arrested so rapidly when a thread breakage occurs during normal spinning that the end of the thread will still be within the effective suction region of the spinning chamber which includes the spinning rotor. However, the customary high thread delivery speeds make such a condition very difficult to fulfill because they require very rapidly-acting sensors, clutches and brakes for arresting the rotating spools and rollers and thus can be met only with very considerable technical expense. The thread breakages which occur naturally when the spinning machine is stopped make it possible to reduce the speed slowly, so that it is not difficult to have the ends of the threads remain within the suction region of the spinning chamber but, when the chamber is opened for cleaning of the rotor or for any other reason, the ends of the threads still generally slide out of the thread draw-off channel and thus prevent an automatic reattachment.
For this reason, it has been proposed in Czech Pat. No. 120,497 to provide a movable tube having an ejector nozzle located between a pair of draw-off rollers and a wind-up mechanism of the spinning machine. However, this mechanism is complicated and still does not guarantee the certain repair of the thread breakage. Furthermore, even if the thread repair is successful, there is the possibility of an undesirable change in the local thickness of the thread or excessive twisting thereof.